1. Field of the Invention
The invention relates to a side air bag apparatus and a manufacturing method of a side air bag.
2. Description of the Related Art
Japanese Patent Application Publication No. 2008-120207 (JP-A-2008-120207) describes a side air bag apparatus in which an inflator is inserted through an insertion hole in a protruding portion (i.e., mounting portion) formed protruding below a side air bag, and the inflator is fastened airtight to the side air bag by fitting and crimping a ring clamp around the outside of the protruding portion.
However, with a structure in which the protruding portion of the side air bag is simply crimped to the inflator using a ring clamp as in the side air bag apparatus described above, the outer periphery of the bag near the crimped portion is constricted and thus will not easily inflate. As a result, when the side air bag receives a supply of gas from the inflator and consequently inflates and deploys, the pressure of the gas may tend to concentrate near the crimped portion.
One way to combat this is to increase the curvature radius of the contour of the outer periphery of the bag so that bag is not as restricted near the crimped portion. The problem with this approach, however, is that the restraining area of the side air bag ends up being decreased by a corresponding amount.